The present invention relates to the field of intraaortic balloon pumps, and more particularly to methods and apparatus for the insertion of such balloon pumps.
A conventional intraaortic balloon pump (IABP) consists essentially of a balloon or bladder which is mounted at the tip of an inflation tube. The balloon may have dimensions of approximately one and one-half centimeters diameter by twenty-two centimeters length, and is initially uninflated. In order to insert the balloon, it is folded or otherwise compacted so that its maximum diameter is approximately that of the inflation tube, or about three to six millimeters.
In a basic variation of the conventional Seldinger technique, such an IABP is inserted via a minor artery by first using a guide wire and dilator to establish a path to the desired location in the aorta, and extending a sheath and dilator along the guide wire to its end. The dilator is removed, leaving the sheath in place. Finally, the folded or wrapped balloon is inserted by pushing its inflation tube through the sheath, thus positioning the balloon at the desired spot. This insertion procedure requires that the balloon occupy a relatively small space.
A number of constructions have been proposed in which a balloon is compacted by inserting a special wrapping wire through the catheter to engage the tip of the balloon, and the wire is turned to turn the balloon tip with respect to the catheter. This twists the balloon around the wrapping wire or a central balloon supporting member. Constructions of a more tangential nature are also known in the field of balloon catheterization, wherein a highly extensible balloon is inflated within an artery to widen the arterial passage. Unlike the balloon of an IABP, the balloons used for this purpose generally have a relaxed or uninflated state which is already highly compact, so that insertion mechanisms are not clearly analogous. Examples of some of the foregoing constructions are shown in U.S. Pat. Nos. 4,362,150 of Lombardi, et al.; 4,531,512 of Wolvek et al.; 4,311,133 of Robinson and 4,292,974 of Fogerty. Other constructions provide a rotatable support member about which the balloon is rolled or twisted, possible with the aid of an external balloon-restraining or engaging member.